Recoil buffer for guns



April 22, 1958 RECoIL BUFFER FOR GUNS Filed Feb. 28. 1952 F. W. SAMPSON HAL INVENTO United States REooIL BUFFER `non GUNS Frederick W. Sampson and Allen L. Everitt, Dayton,

Ohio, assignors tov General Motors Corporation, Detroit, Mich., a corporation of Delaware Application February 28, 1952, Serial No. 273,831

1 Claim. (ci. en -19s) resistance opposing relative movement between the buffer elements, or the frictional damping, is proportional to the impact transmitted to the buier assembly.

Specifically, the buffer assembly com-prises a cylinder rigidly mounted in the butt stock of the gun. Within the bore of the cylinder, a piston provided with frictional damping means, is disposed for movement relative to the cylinder upon recoil of the gun. The frictional damping means associated with one end of the piston, comprises one or more cushion assemblies. The cushion assemblies include a `resilient annular disc` of rubber-'like material, having a thin metal disc bonded to one end surface thereof `and a metal spring ring or band likewise bonded to the circumferentialsurface thereof. The cushion assembly or assemblies are spring urged against one end face of the piston, the lspring being preloaded. Upon relative movement between the cylinder and piston and dependent upon the magnitude of the impact, the resilient discs will be compressed along their longitudinal axes with a consequent radial expansion at their circumferential surfaces. Coincident with the circumferential expansion of the resilient discs, the metal spring ring, bonded thereto, will likewise be expanded, thereby increasing the frictional resistance to relative movement in proportion to the mag- `nitride of the impact.

The magnitude of the impact transmitted to the piston varies inversely with respect to the weight of an ammunition belt lifted through a linkage mechanism by means of a reciprocally mounted member during its movement in recoil. Hence, lesser impacts and lesser recoil movements are obtained when the ammunition belt is full, and greater impacts and greater recoil movements are obtained as the ammunition belt is progressively depleted of Acartridges. High frequency vibrations are absorbed by loading the cushion assemblies directly.. That is, the high frequency vibrations are damped by the resilient discs. However, the low frequency vibrations are damped by the frictional resistance between the cushion assemblies and the walls of the buier cylinder.

The reciprocally mounted member, movable in recoil, is operatively connected to the bolt, the belt feeding mechanism and the cartridge feeding and ejectingmechanism, and is actuated in recoil by movements of any suitable means under the urge of a portion of the rapidly expanding gases of discharge when the gun is red. The impact absorbed by the spring of the butler assembly and a tube driving spring compressed during the recoil movement of the reciprocally mounted member, in essence The aforementioned and other arent O 2,831,404 Patented Apr. 22, 1958 form a double acting buffer which effects frictional damping in both directions to thereby control the rate of movement of the reciprocally mounted member in -counter recoil after the recoil movement thereof has been checked by the buffer assembly. As the ammunition belt is progressively depleted of cartridges, the magnitude of the impact, between the reciprocally mounted member and the piston of the buffer assembly during the recoil cycle, increases with a consequent increase in the frictional damping effect of the buier assembly and a greater recoil. Iny this manner, the counter recoil cycle remains substantially constant and the recoil buier assists in maintaining a substantially constant rate of lire, practically independent of the magnitude of the recoil impact.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to theaccompanying drawing, wherein like reference characters in the several views denote similar parts.

-In the drawing:

Fig. 1 is a longitudinal view, showing the gun partly in section and partly in elevation. t

Fig. 2 is an enlarged, longitudinal, sectional view of the recoil buffer assembly.

Fig. 3 is a perspective view of the cushion assembly utilized in the present invention.

Referring more particularly to Fig. l of the drawing, the gun generally comprises a housing member 1 having attached thereto at one end a butt stock 2 and 4at the other end a barrel 3. A recoil buffer assembly 4 is mounted on the butt plate 5 of the stock 2, the piston rod 6 of which extends into the housing cavity 7. The rod 6 has attached to one end thereof a plug 8. Any suitable means, known in the art, may be utilized to transmit recoil movement to the bulfer. For example it may take the -form of means actuated by a portion of the rapidly expanding gases of discharge when the gun is tired. However this mechanism forms no part of the present invention. i

A tube 19 is supported by the barrel 3, the tube 19 having a bore 20 within which a rod 21 is mounted for reciprocal movement. -A shoulder 22 is formed in the rod 21 adjacent one end 23. Adjacent the end 23 of the rod, a tubular member 25 mounted for reciprocal movement within the housing '1, is attached to the rod by means of a cross pin 26 The tubular member is provided with an integral boss 27 adjacent its other end 30 which is operatively k connected to the reciprocally mounted bolt 28 within the housing 1. Attached to the plug 8 is a spring guide" 31 which projects into the bore 29 of the tubular member 25. Surrounding the spring guide 31, and engaging at one end the plug 8 and at the other end surface 23 of rod 21, is a driving spring 32. The recoil of the gun is transmitted to the assembly comprising rod 21 and tubular member 25 which then moves in recoil. During the movement of tubular member 25 in recoil, the bolt 28 is moved Ito the position it is shown in in Fig. 1.

The bolt 28 has attached thereto a cam actuator assembly 33 which sequentially actuates an ammunition feeding belt mechanism, and a cartridge feeding and ejecting mechanism of conventional design asis well known in the art, during movement of the bolt 28 to the position it is shown in in Fig. l. The ammunition belt is shown generally at 34 with a cartridge 35 therein, and is adapted to be moved transversely through openings in the housing 1, not shown. Continued movement of the tubular member 25 in recoil results in the engagement of endv 30 with plug 8 that is attached to the piston rod 6 of the recoil buffer.

Referring to Fig. 2 the recoil buier 4 comprises a cylinder 36 having internal threads 37 at one end and a pair of holes 3S and 39 inits sidewalle adjacent the other end. A cap member 40 engages the threads 37 and forms one end wall of the cylinder. The cap 40 is provided with an aperture 41l through whichl the piston rod 7 extends. An annular plate 42, having projections 43 and 44, which project through the openings 38 and 39 of the cylinder 36, forms the other end wall. Cap member 45 having openings 46 and 47, is provided with a shoulder 48 at one end dening a channel 49 by which the butter assembly 4 is attached to the butt plate 5. Within the capl member 45 are disposed a plurality of butt stock cushion springs 50 and 51 which provide for cushioning movement of the annular plate 42 and its associated buffer cylinder 36 within the openings 46 andv 47` of the capv member.

Cylinder 36 is provided withy a` plurality of slots 52 adjacent one end and a plurality of holes 53 adjacent the threads 37 of the other end` The function of the holes 53 and the slots. 52 is to allow the free ow of air to and from the bore 54 of the cylinder duringl movements :t

of a piston 55 mounted therein. Abutting the head end face 56 of the piston are one or more cushion assemblies 57. The cushion assemblies 57 are held' in engagement with the face .16 of the piston by means of a preloaded spring 58 mounted between the end wall of the cylinder dened by the annular plate 44 and the head end of the piston 55.

Referring to Figs. 2 and 3 of' the drawing, the cushion assembly 57 comprises an annular resilient disc 59 of rubber-like material, such as natural rubber, or a synthetic copolymer such as neoprene, having a thin metal disc 60 bonded to one end face thereof and a metal spring ring orband 61 bonded to the circumferential surface thereof. The load of the spring 58, for example thirty pounds, is sufficient so that upon transmission of the recoil impact to the piston 55, the resilient annu` lar discs of the cushion assemblies will be compressed along their longitudinal axes with a consequent expansion of their peripheral surfaces before the spring S will tend to be further compressed. In this manner, and dependent on the magnitude of the impact transmitted to the piston 55, the peripheral expansion of the resilient annular discs 59 will causea similar expansion inthe metal rings 61, split at 64, which are bonded tothe peripheral surfaces of the resilient annular, discs. Hence, the frictional resistance opposing relative movement between the piston 55 and thecylinder 3,6 electively damps the recoil impact. Depending4 upon. the amount of frictional damping desired, one or more, cushion assemblies, cooperating with the piston S5, may be provided.

High frequency vibrations are absorbed by loading the cushion assemblies directly. Low frequency vibrations are absorbed or damped' by the frictional resistance between the cushion assemblies and the walls of the buffer cylinder. The cushion assemblies are constructed in wafer form to control stability of frictional damping. Moreover, by reason of stacking the cushion assemblies, added frictional damping is effected between the cushions due to radial iow` of the resilient discs during vcircumferential expansion. In addition the frictional damping of each cushion assembly can be varied by altering the composition of the resilient disc to change the spring rate thereof.

As the recoil buer, by means of the cushion assemblies associated with the piston theerof, provides impact sensitive frictional damping, the counter recoil cycle of tubular member 2S and rod 21 remains substantially constant at the desired rate of re. The tubular member 25 and the rod El are moved in counter recoil by the combined action of spring 58 and driving spring 31. ln operation the two springs and the buffer piston control movements of the rod 21 in both directions. The recoil impact transmitted to the piston increases as the ammunition belt is progressively depleted of the cartridges 35. However, by reason of the impact sensitive frictional damping of the recoil buffer 4, an increase in the recoil impact results in an increased frictional damping. In this manner, the counter recoil cycle isrmaintained substantially constant.

While the embodiment'of the present invention as herein disclosed, constitutesl a preferred form, it is to be understood that other forms might be adopted,

What is claimed vis as follows:

A ,gun having in combination, a housing, a barrel operatively connected to and supported by said housing, a gun stock operatively connected to and supported by said housing, a reciprocally mounted member within said housing and movable in recoil, and a recoil buffer assembly including a movable cylinder operatively connected to said stock member and a piston having a head portion disposed within said cylinder and a rod portion extending outside of said cylinder engageable by said reciprocally mounted member, the operative connection between said cylinder and stock including a cap member attached to said stock, one end of said cylinder being supported by said cap for movement relative thereto, and spring means between the cap member and said one end of the cylinder for cushioning cylindermovement, upon recoil of said reciprocally mounted member.

References Cited in the le ofvthis patent UNITED STATES PATENTS 32,762 Fuller July 9, 1861 1,424,773 Payne Aug. 8, 1922 1,425,808 Thompson Aug. 15, 1922 1,822,079 Bull et al. Sept. 8, 1931 1,896,454 Marek Feb. 7, 1933 1,936,389 Hallquist Nov. 21, 1933 2,010,623 Bugatti Aug. 6, 1935 2,093,169 Holek Sept. 14, 1937 2,144,951 Williams Jan. 24, 1939 2,379,461 Simpson July 3, 1945 2,732,766 Weiss et al. Ian. 3l, 1956 FOREIGN PATENTS 325,090 Great Britain Oct. 28, 1929 

